The way the stomach detects and tells our brains how full we are becomes damaged in obese people but does not return to normal once they lose weight, according to new research from the University of Adelaide. Researchers believe this could be a key reason why most people who lose weight on a diet eventually put that weight back on. In laboratory studies, University of Adelaide PhD student Stephen Kentish investigated the impact of a high-fat diet on the gut's ability to signal fullness, and whether those changes revert back to normal by losing weight.